Single Wall Carbon Nanotube (Swcnt) N02 Gas Sensor


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Jyoti, Ms and Khushbu, Ms and Sharma, DS and Bairwa, MK and Eshwar, T and Agarwal, PB and Kothari, P and Singh, AK and Kumar, A (2016) Single Wall Carbon Nanotube (Swcnt) N02 Gas Sensor. In: International Conference on Advances in Nanomaterials and Nanotechnology (ICANN-2016), November 4-5, 2016, Jamia Millia Islamia, New Delhi (INDIA). (Submitted)

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Notrogen dioxide (NO2) gas sensors are important for the safety of environment and living beings. N02 gas is a filthy-smelling air pollutant from fossil fuel combustion, road traffic, etc and is one of the cancers causing pollutants [I]. Gas sensors based on Carbon Nanotubes (CNTs) are used for improving the gas sensitivity due to high surface area to interact with target gas molecules [2]. Basically, in CNTs based gas sensors, resistance changes when a particular gas molecules are adsorbed on the surface from the surroundings [3]. CNTs gas sensors are classified as chemi-resistive, chemi-capacitive and chemi- field effect transistor [4]. The simplest sensor architecture is the chemiresistor, which consists of two metal electrodes connected by a SWCNT film. Here, we report fabrication and characterization of SWCNT cherniresistive sensor for N02. Functionalization of SWCNTs is performed by oxidation in nitric acid (HN03) for 3 hours. To confirm the attachment of -COOH group on SWCNTs, FTIR spectroscopy (Bruker optic tensor 37) was carried out. A SWCNT-COOH dispersion of 3mg/mL was prepared in DI water by using horn type sonicator (model VCX 750). A thin film of functionalized SWCNTs dispersion was drop-cast over fabricated gold micro electrode structure on silicon substrate with the help of l .5µL micropipette. The SWCNT chemiresistor was kept at room temperature until the DI water evaporates, followed by drying at a temperature of I 00 °C. The fabricated gas sensor was exposed to N02 in an enclosed chamber and the response was measured at concentrations up to 50 ppm at room temperature. Sensitivity of fabricated chemiresistor was measured at different concentrations from IO ppm to 50 ppm. Initially sensor was purged with dry air for 15 minute and initial resistance was measured 4.24 kohm. Exposure time of dry air and N02 gas was 5 minute each. Resistance of chemiresistor decreases in presence ofN02 gas at IO ppm and recovers partially to its original value after removal N02. Variation of sensor resistance with NO2 concentration (10ppm-50ppm). SWCNTs chemiresistor shows resistance variations from 4.24 kohm to 2.89 kohm when exposed to N02 concentration from IO ppm to 50 ppm. Corresponding calculated sensitivities are 12.16% at IO ppm and 31.88% at 50 ppm. This study shows the potential of SWCNTs for room temperature N02 sensor applications in environmental monitoring.

Item Type: Conference or Workshop Item (Paper)
Subjects: Semiconductor Devices > Sensors and Nanotechnology
Divisions: Semiconductor Devices
Depositing User: Mr. Rohit Singh
Date Deposited: 20 Jun 2017 09:48
Last Modified: 20 Jun 2017 09:48

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